Two events occur in an inertial system k as follows. event 1: x1 = a, t1 = 2a/c, y1 = 0,z1 = 0event 2: x2 = 2.6a, t2 = 1.5a/c, y2 = 0,z2 = 0what is the velocity of the frame k' in which these events appear to occur at the same time? express the velocity vector using the variables a and c and the unit vectors, i, j, and k; for example, 2i + 2j is a vector which bisects the x and y axes.

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.